1. Field of the Invention
This invention relates to wet extraction cleaners. In one of its aspects, the invention relates to a wet extraction cleaner with a centrifugal separator adapted to separate entrained liquid, foam, and debris from a working air flow during an extraction process. In another of its aspects, the invention relates to a wet extraction cleaner with a flexible architectural structure with a separate liquid separator and recovery tank. In another of its aspects, the invention relates to a wet extraction cleaner with a recovery tank that is easier to empty. In yet another of its aspects, the invention relates to a wet extraction cleaner with an air-liquid separator that minimizes foam generation of extracted fluid. In still another of its aspects, the invention relates to an extraction cleaner with a centrifugal air-liquid separator adapted to minimize the pressure drop between the working air inlet and exhaust outlet for more efficient extractor operation. In yet another of its aspects, the invention relates to a wet extraction cleaner with an air-liquid separator configured for mounting in a variety of locations on an extraction cleaning machine, including mounting to or near a fluid recovery tank, or alternatively mounted remotely from the recovery tank such as on an upright handle portion separated from the fluid recovery tank. In still another of its aspects, the invention relates to a wet extraction cleaner having a relatively low profile of an air-water separator and recovery tank.
2. Description of the Related Art
Extractors are well-known suction cleaning devices used for deep cleaning carpets and other fabric surfaces, such as upholstery. Most carpet extractors comprise a fluid delivery system and a fluid recovery system. The fluid delivery system typically includes one or more fluid supply tanks for storing a supply of cleaning fluid, a fluid distributor for applying the cleaning fluid to the surface to be cleaned, and a fluid supply conduit for delivering the cleaning fluid from the fluid supply tank to the fluid distributor. The fluid delivery system can optionally include valves and/or pump assemblies for mixing and/or pressurizing the fluid for application by the fluid distributor.
The fluid recovery system typically comprises a recovery tank assembly, a suction nozzle positioned at the surface to be cleaned and in fluid communication with the recovery tank via a working air conduit, and a suction source in fluid communication with the recovery tank. The recovery tank assembly typically comprises an air-liquid separator configured to separate entrained liquid from a working air flow to prevent liquid ingestion into the suction source. An example of an upright extractor having representative fluid delivery and fluid recovery systems is disclosed in U.S. Pat. No. 6,131,237 to Kasper et al., which is incorporated herein by reference in its entirety.
U.S. Pat. No. 7,293,324 to Chui et al. discloses a wet/dry vacuum cleaner with a centrifugal flow air-liquid separator that includes a liquid collection chamber integral with and below the cylindrical separator and a controller in the liquid collection chamber to stop operation of a suction source when the liquid level within a liquid collection chamber rises to a predetermined level. The separation chamber comprises a cylindrical housing having a tangential inlet and a cylindrical wall that guides the liquid-entrained air in a circular path around the internal perimeter of the cylindrical housing. An exhaust outlet conduit of the separation chamber extends upwardly from an upper end of the separation chamber and is in communication with a remote suction source. The cylindrical collection chamber is disposed below the separation chamber and further comprises a float assembly adapted to move vertically along the inside wall to actuate a microswitch that selectively disconnects power to a vacuum motor when the fluid in the collection chamber rises to a predetermined level.
U.S. Pat. No. 7,048,783 to Ponjican et al. discloses a centrifugal flow air-liquid separator for a wet/dry vacuum cleaner. The separator comprises a separation housing having an open bottom that forms a liquid and debris outlet and further includes an exhaust standpipe protruding from the top wall and defining a dry air exhaust conduit therethrough. The exhaust standpipe is fluidly connected to a suction source mounted on top of the separator. The separator further comprises an offset inlet that is tangentially disposed at an upper portion of the housing. The inlet further comprises a lead-in track that extends from the inlet and at least partially around the circumference of the separator chamber to guide the incoming air-liquid mixture in a downward spiraling flow path toward the separator outlet and into a fluid collection chamber.
U.S. Pat. No. 1,568,413 to Peebles discloses a centrifugal steam entrainment-trap separator comprising a conical casing with a vapor discharge pipe extending upwardly through the center of the bottom wall and configured for connection to a remote vacuum source. The separator further comprises a liquid discharge duct connected to the bottom wall of the separator casing. A tangential working air inlet pipe is positioned near the lower portion of the casing. The separator is said to separate liquid-foam mixtures commonly encountered during various industrial processes such as milk evaporation and plant tannin extraction. In use, a liquid and foam mixture is delivered to the separator at high velocity where a combination of the swirling action, gravity, and friction against the tapered casing walls effectively breaks up the foam bubbles and separates the liquid from the vapor. The separated liquid exits the separator through the liquid discharge duct protruding from the bottom wall while the exhaust air exits the separator via the vapor discharge pipe.
U.S. Patent Application Publication No. 2006/0156699 to Kim discloses a cyclonic separator for a dry vacuum cleaner having a tangential inlet disposed at a lower portion of the separator housing. An exhaust pipe protrudes upwardly through the center of the separator bottom wall and has an open top thereby forming an exhaust conduit that is fluidly connected to a remote suction source. A dirty air flow is introduced into the separator through the inlet and swirls along the inside wall of the separator housing. Debris is centrifugally separated from the air stream and deposited into a cylindrical collection chamber surrounding the separation chamber. Exhaust air flows downwardly through the exhaust pipe to a suction source.
U.S. Pat. No. 3,776,385 to Maciula et al. discloses a hydrocyclone for separating heavier liquids and solids from a lighter liquid medium. The hydrocyclone comprises an upright cylindrical portion and a tangential liquid inlet fluidly connected thereto through. The cylindrical portion is closed by a top having an outlet. A downwardly-tapering conical portion having an upper diameter slightly less than that of the cylindrical portion is positioned coaxially within the cylindrical portion to define an annular space between the conical portion and cylindrical portion. In operation, a mixture of two immiscible liquids with some solids is injected into the hydrocyclone, and separated by centrifugally forces by movement of the heavier liquids and some larger solid particles outwardly towards the cylindrical wall and downwardly through the annular space into an underflow pot. At the same time, remaining solids entrained in the lighter liquid are separated in the conical portion and exit though a vertical opening at the bottom thereof into the underflow pot. The lighter liquid medium then flows upwardly through the outlet.
Additional examples of hydrocyclone-type separators are disclosed by U.S. Pat. Nos. 1,737,680 to Pinkham; 4,175,036 to Frykhult; 4,308,134 to Lilleker et al.; 4,816,156 to Brombach et al.; and 6,024,874 to Lott.